/Engine/Source/Runtime/Engine/Classes/Engine/CloudStorageBase.h
Write a key/value pair to the cloud. A CSD_KeyValueWriteComplete. delegate will be called when it completes (if this function returns true).
true on success, false otherwise.
virtual bool WriteKeyValue ( const [FString](API\Runtime\Core\Containers\FString) & KeyName, const [FPlatformInterfaceData](API\Runtime\Engine\Engine\FPlatformInterfaceData) & Value )